Here’s my little blip of embarrassing stupidity recently. I went to Mallorca 3 weeks ago. Rode 500k all over the mountains and the whole time I was bothered by my noisy gear train. I looked it over and nothing seemed amiss but man it was annoying. Almost a grinding noise. I thought maybe it’s the waxed chain so I put some oil on but no, still loud. Maybe it’s the Force cassette I thought. Nope. Can you guess what I’d done wrong?